Drilling bit



Se t. 10, 1929, G. B. LOUDERBACK DRILLING BIT Filed Oct. 8, 1928Inventor, $60236 Blade/back, a r,- ver A orn/ey.

Patented Sept. 1%, 1929.

tin-tree s'rarss,

GEORGE E. LO'UDEEIBACLZ,

Wye

earns oerie s.

0F COMPTON, GALIYEEQRNIUh.

LDRILLHTG- BIT.

Application filed October 8, 1928. Serial No. 311,102.

In this specification, and the accompanying drawing, 1 shall describeand show a preferred form of my invention, and specifically mentioncertain of its more important objects. I do not limit myself to theforms disclosed,

since various changes and adaptations may be made therein withoutdeparting from the essence of my invention as hereinafter claimed; andobjects and advantages, other than those specifically mentioned, areincluded within its scope.

I My invention relates to bits for deep-well drilling, and particularlyto bits of this kind for resisting all of the operating shocks andstresses that may be imposed upon such cutting blades, withoutsubjecting the fastening bolts thereto; third, to supply improved meansfor discharging a circulating jet in ad- Vance of the cutting edges ofthe blades; and,

fourth, to accomplish the stated objects in a simple and relativelyinexpensive construction of great inherent strength.

My objects are attained in the manner illustrated in the accompanyingdrawings, in WlllCl1- Figure 1 is a front elevation of my completeinvention;

Figure 2 is a side elevation of the same;

1}igure 3 is a plan view of the top of the too Figure 4 is across-section of the tool taken on the lines 44 of Figs. 1 and 2;

Figure 5 is a similar cross-section taken on the lines 5-5 of Figs. 1and 2;

Figure 6 is a front elevation of one of the detachable cutters of thetool by itself; and

Figure 7 is a side elevation of this cutter.

Similar reference numeralsrefer to similar parts throughout the severalviews.

My improved bit comprises a bit-body having a wedge-shaped lower portion11, of ap proximately, elliptical section; a cylindrical intermediateportion 12;- and a tapered screw pin 13 at the top, adapted for engaginga standard tool-joint or the like. The lower end of the body is slottedalong its major transverse axis, and cutting blades 14 are inserted inthis slot which they closely fit. A narrower transverse slot 15 alongthe major axis, extends upward a considerable distance from the top ofthe first slot, and the two. slots effectively bifurcate the tool body,so as to permit the cutters to be tightly gripped in the lower slot bymeans of a bolt 16 through each of them and the tool body. The boltholes 17 in the cutters are of slightly larger diameter than the bolts,so that no transverse operating stresses can be imposed upon the boltsin view of the fact that the cutters are otherwise positioned to resistsuch stresses. Each cutter has a transverse flange 18, across its rearface, engaging the lower end of the tool body and capable of supportingthe weight of the tool string above it. Each cutter also has anLip-standing arm 19, fitted snugly into a longitudinal peripheral groovein the tool body, adapted for preventing the cutter from turning in thedirection of its engage- Y ment. I

The tool body has a longitudinal slot exso tending upwardly from itslower extremity in the plane of its minor transverse axis, and of alength along this axis that is more than half of the thickness of thetool body so as to more than bisect the slot into which the cut ters arefitted. A plate 20 is fitted into this longitudinal slot with its inneredge spaced from the end thereof, as shown at 21. Its outer edge is thenwelded to the tool body, as shown at 22. The inner longitudinal edges ofthe cutters abut against plate 20, and their inward stresses areresisted thereby. Thus an inward stress upon either cutter will not betransmitted to the other.

It will be seen from the foregoing description that the cutters of myimproved tool are adequately positioned to withstand all of theoperating shocks and stresses to which they can be subjected. In thefirst place, they are strongly gripped within the bifurcation of thetool body by means of the tension of bolts 16. Secondly, the weight ofthe tool string is supported by flanges 18. In the third place, theinward thrust of the cutters is resisted by plate 20. And, finally, thecutters are prevented from turning by means of flanges 18 and arms 19.The bolts 16 are subjected only to the tension required to grip thecutters between the bifurcated lower legs of the tool body, and do nothave transverse stresses imposed upon them.

For the purpose of delivering circulating water at the cutting edges ofthe bit, I form the upper portions of the body with two, internalpassages 23, leading downwardly and outwardly from the top andterminating at the periphery of the tool body just below body portion12. At the latter points, pipes 24 are welded to the body and continuethese water courses downward to discharge just above the respectivecutting edges, at25, and just in advance of the cutters.

It will be seen that the invention that l have described and illustratedcomprises, in efiect, a fish-tail bit of improved construction, havineasily removable cutters that in serv ice are very firmly positionedwithout danger of subjecting the attaching bolts to transverse stresses.The lower edges 26 of the cutters are adapted for drilling, and thelaterally extending ed es 27 are adapted for reaming to maintain thegauge of the hole.

Having thus fully described my invention, 1 claim: y

A drilling bit having a body, bifurcated at itsforward extremity andcomprising a transverse terminal slot 'intermediately partitioned atsaid extremity; a pair of removable cutters fitted into said slot,abutting said partition and extending from the tool body; and boltspassed through the cutters and drawing the legs of the body together totightly compress the cutters between the walls of said slot; saidcutters being positioned to resist operatmg stresses without sub ectingthe bolts to transverse stress; and the intermediate. partitioncomprising a plate bisecting said slot, slidably fitted within a grooveat right angles thereto and secured to only one of the legs of the toolbody, so that said legs may be drawn toward each other.

GEORGE B. LOUDERBACK.

